Night vision imaging systems are used to enhance vision in low-light conditions and are therefore, commonly employed in the military for use by soldiers, aviators and sailors. The central component of a night vision imaging system is an image intensifier tube which functions to multiply incident light received by the system to produce a display that is sufficiently bright for presentation to a viewer's eyes. Most of these night vision imaging systems also include lens assemblies, battery packs and adjustable mountings, and are manufactured as monocular or binocular assemblies depending upon the specific application.
The night vision imaging systems commonly used by most military aviators are designed as binocular assemblies to provide the aviator with depth perception for flights made during low-light conditions. Such systems are designed to be mounted to an aviator's helmet and are referred to as Aviator's Night Vision Imaging Systems (ANVIS). A helmet mount affixes to the front of the aviator's helmet via screws to provide a method for removably attaching an ANVIS binocular to the helmet and power the ANVIS binocular. A power source consisting of electrical contacts integrated into the helmet mount and a disconnectable battery pack which is affixed to the rear of the helmet during use via hook and loop fasteners, powers the ANVIS binocular. Battery power from batteries contained in the battery pack, is routed to the ANVIS binocular through a cable which is coupled between the contacts of the helmet mount and the battery pack. The ANVIS binocular has a fore and aft slide assembly that operates with the helmet mount to enable the ANVIS binocular to be rotated relative to the helmet, from an operational position to a non-operational position. When the ANVIS binocular is rotated to the operational position, the electrical chin the helmet mount engage electrical contacts provided on the ANVIS binocular to conduct power thereto. Examples of such night vision binocular imaging systems are described in U.S. Pat. No. 4,449,783 to Burbo et al. and U.S. Pat. No. 5,535,053 to Baril et al.
The ANVIS power source works well during its intended primary use mode of providing visual clues to aviators during low-light flight conditions. However, a major disadvantage of the system is that the helmet is required to operate the ANVIS binocular since, power for the binocular is supplied through the helmet mount which is affixed to the helmet. In order to use the ANVIS binocular without the helmet, the aviator must disassemble the helmet mount from the helmet which is difficult. The remaining helmet mount and battery pack must then be electrically connected by the cable which is approximately two feet in length. This makes the system unwieldy and does not promote efficient use of the ANVIS binocular.
Such a disadvantage can have severe consequences when an aviator is downed behind enemy lines and needs the ANVIS binocular separated from the bulky helmet, to escape and evade the enemy.
Accordingly, there is a need for a power source which allows an ANVIS binocular to be used as a hand held unit.